1. Field of the Invention
The present invention relates to an electric zoom camera and, more particularly, to a zooming operation control system.
2. Related Background Art
A t/w switchable camera capable or performing switching between telephoto and wide-angle modes by operating a photographing lens is known. In this t/w switchable camera, a photographing lens can be instantaneously set to a desired focal length by an operation unit located at an upper portion of a camera body. Therefore, a degree of freedom of photography is higher than that of a conventional fixed-focus compact camera. The t/w switchable camera, however, cannot perform photography by an intermediate focal length between the telephoto and wide-angle ranges. For this reason, a zoom compact camera mounting a zoom lens and capable of continuously changing a focal length from the telephoto to wide-angle ranges has become commercially available.
A known zoom compact camera normally has an operation unit for designating switching of a focal length between telephoto and wide-angle directions. While the operation unit is operated, a zoom lens is electrically driven in a zooming direction designated by the operation unit. When an operator removes his or her hand from the operation unit, driving of the lens is stopped. In this manner, a focal length can be arbitrarily set throughout the entire focal length range of the mounted zoom lens. The operation unit, however, must be continuously operated until a desired image magnification is obtained, resulting in a poor operability.
This problem can be solved by moving a photographing lens along a designated zooming direction in accordance with a zooming command and automatically stopping the lens at a predetermined intermediate focal length position. Such a zooming control system will be called "step zoom control" hereinafter.
The present applicant has proposed a t/w switchable camera capable of performing two-shot continuous photography by different focal lengths using a self-timer (U.S. patent Ser. No. 199,142 corresponding to Japanese Utility Model Application No. 62-86562 and the like). By combining the technique of this proposed camera with the above step zoom control, a camera capable of executing the step zoom control in response to one photography operation and executing exposure of a film each time zooming to each focal length is completed can be obtained (this shooting system will be called "sequence zoom shooting" hereinafter).